As is well known, catalytic converters are now present in the exhaust system of automobiles of recent vintage to reduce the polluting effect of the engine exhaust gases, and the engines are supposed to employ unleaded gasoline. Presence of lead in the engine exhaust gases is undesirable because lead poisons the catalyst in the converter. However, as of the date hereof, a great many older model automobiles are still in use and as a result, gasoline vendors provide pumps, particularly self-service pumps, for both leaded gasoline and unleaded gasoline to be used at the option of the purchaser.
Unfortunately, leaded gasoline is significantly less expensive than leaded gasoline, which fact encourages cheating by the motorist, through use of leaded gasoline.
Mandatory nozzle size standards have been applied to gasoline vending pumps to prevent dispensing of leaded fuel into the fuel tanks of automobiles equipped with catalytic converters, for reason, of course, that leaded fuel renders catalytic converters permanently ineffective. The nozzle size standard dictates that the delivery nozzles for unleaded fuel shall not exceed 0.85" in diameter while the delivery nozzles for leaded fuel shall not be less than 0.93" in diameter. A companion standard applies to the filling tube of the automobiles and requires an arrangement that limits the amount of leaded fuel that can be delivered by the standard nozzle, before triggering operation of the automatic shutoff mechanism in the filling nozzle of the vending pump to block flow of additional fuel.
The automative industry response to these standards has been factory installation of restrictor assemblies in the automobile fuel filler tube so as to accept therein only the unleaded nozzle size. These assemblies contain an aperture appropriately sized for receiving the nozzle. Presentation of the nozzle tip through the aperture opens a spring-biased flap or door that otherwise would prevent unimpeded flow of the fuel into the gas tank. Efforts to pump gasoline from the oversized leaded gas nozzle causes gasoline to collect above the flap and triggers the nozzle cut-off mechanism. Prior art describing such restrictor assemblies known to the inventor hereof are U.S. Pat. Nos. 3,880,317; 3,911,977; 4,034,784; 4,185,844; and 4,248,279; these patents being incorporated by reference herein for further understanding of the restrictor assemblies to which practice of this invention applies.
By and large the higher cost of unleaded fuel and the perversity of individual motorists, has resulted in modification of a shockingly high number of converter-equipped automobiles to enlarge the filling tube aperture enough to permit acceptance of leaded fuel nozzles. In a word, the restrictor assembly is mutilated to defeat the intent of the above-mentioned standards; the catalytic converters are ruined.
The harm done by mutilation of the restrictor assemblies goes beyond private violation of the pure air laws. In point of fact, virtually all automobiles pass through many hands between purchase as a new car and ultimate destruction as junk. All successor owners of an automobile with a mutilated restrictor assembly also violate the law, including persons who do not want to do so.
In particular, one class of purchases of second-hand automobiles cares very much about whether or not the restrictor assembly in the gasoline filler tube has been mutilated so as to accept leaded gasoline vending pump nozzles. Any automobile dealer who offers for sale a motor vehicle that has been so mutilated faces substantial fines and other sanctions of law. The used-car dealers face a situation which is almost ironic. The manufacturers have provided tamper-resistant fuel filler restrictor assemblies that virtually cannot be removed and replaced. To comply with the law, the used-car dealers many be required to replace the entire gasoline tank assembly, which constitutes a major expense.
The purpose of this invention is to rectify the unfortunate and almost absurd situation of a mutilated, but unremovable restrictor assembly.
The object of this invention is to provide an insert adapted to resize the gas tank neck opening of the filler tube so as to prohibit entry of the leaded gas nozzle.